Mn1 gene overexpression in multiple meningioma and comparison with typical-atypic meningiomas

Meningiomas are slow-growing extraaxial tumors originating from arachnoidal cap cells, whose biological behavior is mostly benign. Less than 10%of patients with meningioma are followed as multiple. They are seen more frequently in women than in men at the rate of 2/1-3/2. The main causes considered in the etiology include trauma, radiation, congenital factors and predisposition of some malignancies. The MN1 (meningioma-1) gene, which is a gene detected at the break point of sporadic balanced t(4:22) translocation on chromosome 22, has been defined as the meningioma tumor suppressor gene. There are studies suggesting that the MN1 gene, which is thought to be a transcription activator, also plays a role in the development of hematopoietic system malignancies. However, the relationship of this gene with meningiomas has still not been resolved. In this study, it was planned to investigate whether MN1 gene overexpression accompanies multiple meningiomas, whether MN1 gene overexpression has an effect in multiple meningiomas and what kind of role it plays by comparing it with other solid typical and atypical meningiomas. 25 patients with multiple meningiomas, 25 typical meningiomas and 19 atypical meningiomas participated in the study. These three groups are; MN1 gene overexpression, age, gender, location and size of the tumor, epileptic seizure, and histopathological subtype of the tumor were examined. Of the 69 patients included in the study, 49 were female and 20 were male. The mean age of the patients examined was 59, and the mean tumor size was 38x41 mm. In terms of location of the tumor, the most convexity location was seen in all 3 groups and 9 patients had seizure complaints. Twenty-two of the patients were WHO grade II and 47 were WHO grade I. Obtained data were compared statistically. As a result of the study, although MN1 gene expression was significant in female gender, no significant relationship could be established in the evaluations made according to the MN1 gene overexpression score in multiple, atypical and typical meningiomas. Although there was no statistical correlation between patient groups and MN1 gene expression, the MN1 gene expression was observed in 62.3%of the patients in our study, suggesting that the MN1 gene may have a role in the development of meningioma. It is thought that the relationship between the MN1 gene and meningioma will be better understood with different studies to be done and these studies will guide new evaluations in the course of the disease and treatment algorithms. Keywords: Meningioma, Multiple meningioma, MN1 gene